This invention relates to downhole drilling, particularly to downhole drilling for oil, gas, and geothermal, and to horizontal drilling. More specifically, the invention relates to downhole drilling stresses including compressive stress and rotary torque. While drilling, the stresses seen by the drill string may be routed through the drill string to specific components leaving others substantially stress free.
U.S. Pat. No. 7,193,526 to Hall et al., which is herein incorporated by reference for all that it contains, discloses a double shouldered downhole tool connection comprising box and pin connections having mating threads intermediate, or between, mating primary and secondary shoulders. The tool connection further comprises a secondary shoulder component retained in the box connection intermediate, or between, a floating component and the primary shoulders. The secondary shoulder component and the pin connection cooperate to transfer a portion of makeup load to the box connection. The downhole tool may be selected from the group consisting of drill pipe, drill collars, production pipe, and reamers. The floating component may be selected from the group consisting of electronics modules, generators, gyroscopes, power sources, and stators. The secondary shoulder component may include an interface to the box connection selected from the group consisting of radial grooves, axial grooves, tapered grooves, radial protrusions, axial protrusions, tapered protrusions, shoulders, and threads.
U.S. Pat. No. 7,377,315 to Hall et al., which is herein incorporated by reference for all that it contains, discloses a downhole tool string component with a tubular body and a first and second end. At least one end is adapted for axial connection to an adjacent downhole tool string component. A covering, secured at its ends to an outside diameter of the tubular body, forms an enclosure with the tubular body. The covering has a geometry such that when a stress is induced in the sleeve by bending the downhole tool string component, that stress is less than or equal to stress induced in the tubular body. The covering may be a sleeve. Further, the geometry may comprise at least one stress relief groove formed in both an inner surface and an outer surface of the covering.